The present invention relates to a thermosetting resin composition (or a mixture of such materials) useful for semiconductor encapsulants, printed circuit substrates, automobile parts, etc., a process for producing such a composition, molded articles thereof and their uses.
Thermosetting resin compositions are widely used for semiconductor devices, printed circuit substrates, automobile parts, etc., but none of the available compositions is well satisfactory in terms of qualities. Various attempts have been made for improving dynamic properties of the resins at high temperatures. For instance, JP-A 7-331069 and JP-A 7-331070 disclose a method in which a metallic oxide sol is dispersed in a polyamideimide resin; JP-A 8-100107 proposes to polycondensate an epoxy resin by adding a metal alkoxide; JP-A 9-216938 teaches to have a metal alkoxide swollen in a phenol resin before polycondensing it; and JP-A 9-291131 proposes a method in which a metal alkoxide is added to a polyurethane resin and condensed by a sol-gel method. These methods, however, have a problem in that the curing reaction for polycondensation is accompanied by the generation of water and tends to cause swelling at the interfaces of the composite material. Also, none of the proposed techniques concerns means for preventing swelling and cracking which may occur at the interfaces of the composite material with change of temperature.
JP-A 8-199045 proposes a method in which in order to suppress the generation of thermal stress, an alkoxysilane and water are added to an epoxy resin dissolved in an organic solvent, and after the alkoxy groups of the alkoxysilane have been hydrolyzed, the solvent is removed and the remaining material is heated to effect curing of the resin and dehydration of the hydroxyl groups. This method, however, involves the problems concerning generation of water and adhesion at the interfaces of the composite material at high temperatures.
The conventional techniques come down to an expedient for making a composite material by curing a mixture of a thermosetting resin, a silicic compound and water with a base material such as a metal, a ceramic material or other resin. According to this method, water and an alcohol are formed as by-products in the course of curing. These by-producted water and alcohol give rise to various ill effects, such as corrosion of the metallic base, swelling at the interface between base and resin, and cracking or exfoliation of the molded article. Also, −25 the conventional art neglects means for preventing occurrence of swelling and cracks at the base/resin interface incidental to change of temperature.